IF C IS EQUAL TO X AND B IS EQUAL TO D AND THE SQUARES ROUTE OF 26 IS EQUAL TO X WAT WOULD BE THE FOMULA FOR THAT TO FIGURE OUT WAT D IS? I NEED HELP!!!!!

You need a tutor. I recommend you discuss it with your parents.

You are looking for a "formuls", what is needed here is some thinking. I strongly suggest a tutor.